Known current sensors comprise:                an electrical conductor extending along a direction X and in which the current to be measured circulates,        a magnetic field sensor fixed with no degree of freedom to this electrical conductor to measure the magnetic field generated by the current to be measured when it circulates in this electrical conductor, and        a computer programmed to establish the measurement of the intensity of the current to be measured on the basis of the measurement of the intensity of the magnetic field measured by the magnetic field sensor.        
The magnetic field sensor used in this current sensor comprises N magneto-resistive transducers TMi, the resistance of each transducer TMi varying linearly to within ±xi% as a function of the intensity of the magnetic field to be measured within a maximum range [ai; bi] of intensity of the magnetic field to be measured and non-linearly outside of this range, N being an integer number greater than or equal to two and the index i being an identifier of the transducer TMi.
Such a current sensor is, for example, disclosed in the patent application US2011/0227560 or in the application WO2007148028.
In the current sensor of US2011/0227560, a compensation line is implemented to generate a magnetic field Hd of a direction opposite to that of the magnetic field to be measured Hm. More specifically, the intensity of the field Hd is enslaved onto that of the magnetic field Hm to maintain the field Hr resulting from the combination of these two fields Hd and Hm close to zero. It is this field Hr which is measured by the magneto-resistive transducer. Since the field Hr is maintained close to zero, the magneto-resistive transducer works within the range in which it is most linear, which increases its linearity.
The presence of such a field Hd makes it possible to increase the range of measurements of the magneto-resistive transducer. “Range of measurements” here designates the maximum range over which the response of the magneto-resistive transducer varies linearly to within plus or minus x % as a function of the intensity of the field Hm to be measured, where x is a predetermined constant.
The linearity to within ±x % over a range [a, b] is defined as follows: whatever the value of the intensity of the field Hm to be measured within the range [a; b], the absolute value of a ratio β, expressed as a %, is less than the constant x, where the ratio β is defined by the following relationship: β=(Rm(Hm)−D(Hm))/D(Hm), in which:                Rm(Hm) is the value of the signal generated by the magneto-resistive transducer when it is placed in the field Hm,        D is the straight regression line minimizing the deviations, according to the least squares method, between this straight line and the different values Rm(Hm) measured over the entire extent of the range [a; b],        D(Hm) is the value of the straight regression line for the field Hm.        
Hereinafter in this description, the range [a; b] is the maximum range, that is to say the greatest, over which the linearity of the magneto-resistive transducer is less than x %. Thus, setting the value of x makes it possible to also set the value of the bounds of the range [a; b]. Typically, the range [a; b] for a given value x is measured by trial and error.
In these known sensors, the energy consumption to generate the field Hd is significant.
To increase the range of measurements of a magneto-resistive transducer, it has also already been proposed elsewhere to generate a constant magnetic field parallel to the direction of easiest magnetization of the free layer of the magneto-resistive bars forming this magneto-resistive transducer. Typically, this direction is at right angles to that of the field Hm to be measured. The presence of this constant magnetic field makes it possible to effectively increase the range of measurements of the magneto-resistive transducer but to the detriment of the sensitivity of this transducer.
Prior art is also known from US2006/291106A1.